Many of us experience multiple queues on an average day. If they move quickly, they're soon forgotten. But a slow line can seem to last forever and can put a drag on an entire day.

What separates a good queuing experience from a bad one, however, is not just the speed of the line. How the wait makes us feel and line fairness (nobody likes line-jumpers) can have a greater impact on our perception of a queue than the amount of time we spend in it. And while waiting time is often hard to cut down, perception can be altered with good line design and management.

"A wait is a psychological state," Don Norman, a user experience pioneer and director of The Design Lab at UCSD, said in a phone interview. "In that way, it's a matter of design, of trying to understand the psychology of the people waiting but also their boredom and frustration. It requires a human-centered design perspective, from the points of view of both the people doing the servicing and the people waiting in line. That isn't hard, but you have to develop a sensitivity to it or realize why it might be important."

Mirror, mirror, in the hall

When it comes to waiting, perception is more important than reality. To understand how, think of the mirrors that often line an elevator hall. The story goes that they started being installed during the postwar boom in highrise buildings as a response to complaints of long waits for the elevator.

"Putting mirrors next to elevators is a way to distract people for a minute or two so they can adjust their ties or their hair and make sure they're looking great," Richard Larson, a queuing theory expert and professor at the Massachusetts Institute of Technology, said in a phone interview. "You can do something to reduce the complaints even though the duration of the wait remains unchanged."

A similar example comes from another story about an airport getting complaints for the long waits at the baggage carousel. After trying, fruitlessly, to make baggage delivery faster, the airport simply moved the arrival gates outside of the main terminal, making people walk six times longer to get their bags. Time was spent walking instead of waiting around and complaints dropped to almost zero.

No shopper left behind

Queuing theory, or the mathematical study of waiting lines, was inaugurated over 100 years ago by Danish engineer A.K. Erlang, who came up with formulas to calculate how many lines and operators telephone companies needed for a smooth service. "He invented queuing theory and even though about 10,000 articles have been written on queuing theory since, his formulas are still the most widely used today," said Larson.

Just like a busy signal, bad lines can be damaging to businesses, and a single catastrophic line experience can stay with us for a long time. Larson tells of an incident he suffered years ago in a department store "that infuriated me, when maybe 15 or 20 people who had arrived after me got their things before I did while I was there, just waiting. Three weeks later I was still angry and I made a lifetime pledge to never, ever patronize that store again."

Larson calls this a "slip and skip," or a violation of the first come, first served rule in which a newcomer joining a faster line skips over someone waiting in a slower line, who therefore slips. "Theorem number one: for every slip there's a skip, but it's not a zero sum game psychologically. The person who skipped may not even be aware of it, but the level of anger and dismay of the victim of the slip can actually get up to a point of violence, or queue rage," he added.

One is better than many

"Slips and skips" are bad because they lack fairness, a crucial aspect of how we value a service. Locksmiths, for example, sometimes intentionally take longer to pick a lock, even if they could do it in seconds, according to psychologist Dan Ariely. The assumption is that, otherwise, people would be irked to pay for just a few seconds worth of work, or feel that the lock wasn't safe to begin with.

Parallel checkout lines in a supermarket in Brazil. Space limitations usually make it harder to set up a serpentine line for shopping carts. Credit: YASUYOSHI CHIBA/AFP/AFP/Getty Images

Multiple parallel lines, each in front of a register, can be great if you're in a fast one, but can feel very unfair if you're stuck. They also make people switch from one line to another in search of the fastest (known as "jockeying"), abandon the queue out of desperation ("reneging") or not join the queue at all, fearing a long wait ("balking").

That's why businesses are increasingly switching to the serpentine line, probably the most significant design improvement the humble queue has ever received. It's unclear who first implemented it -- American Airlines, British Airways, Chemical Bank (now Chase) and Wendy's, among others, all say they did -- but it's now ubiquitous in airports and most large stores. In a serpentine line, all customers are funneled into a single queue and then dispatched to the first available counter. Compared to parallel lines, the serpentine triumphs in the key department of fairness: it's strictly first come, first served, so no one arriving after you can be served before you.

High end supermarket Whole Foods, which has pioneered the serpentine line among grocers and employs "line managers" to direct customers, also uses a hybrid system in some of its stores, in which customers line up in parallel queues of different colors and must keep an eye on a screen that replicates the same colors. Once a register becomes available, it is automatically assigned to one of the color-coded lines and its number flashes onscreen.

A serpentine line at a Whole Foods store in Los Angeles. Credit: Bloomberg/Bloomberg/Bloomberg via Getty Images

But it's not always easy to tell which system is in place in any given establishment, and not all stores display the same amount of care for line signaling. "Many retail places that I go to haven't really thought about this. My local drugstore, which is an international chain, uses what I call 'accordion' queue management: they'll only bring up another checkout person if the line exceeds some threshold. And that's fine, but there are no lines on the floor and no stanchions to indicate where the queue starts and whether you should queue up separately for each station or have one master queue. That's an example of where line design is necessary, but this huge multibillion-dollar chain doesn't seem to focus on it," said Larson.

A sign at an Apple store in Sydney separates people who intend to buy an iPhone outright from those who want to buy it on a plan. Credit: WILLIAM WEST/AFP/AFP/Getty Images

If you've ever stood in a line for a long time only to get to the front and be told it was the wrong one, you'll understand the importance of clarity when designing queuing areas. But investment and effort in this type of organizational design seems uneven. "There are places that invest a lot in this, like theme parks, but I'm otherwise surprised by the lack of attention," said Don Norman. "My suspicion is that there's a lot of attention to all sorts of features of a building and its interior space, but very little attention to the way that people work inside them. And then when the people come they have to make do with the way things are laid out."

The Disney way

Indeed, the golden standard of line design and management can be found in theme parks. Waiting lines are such an integral part of that experience that companies are not afraid to invest. Disney has a dedicated underground facility called the Operation Command Center, located under the Cinderella Castle at the Walt Disney World Resort near Orlando, where waiting times and queues are monitored and managed constantly.

Some of the tricks of the trade theme parks use to make waits more bearable are "queue chunking" -- disguising the line around corners or walls to make it appears shorter -- and inflating the waiting times posted at each attraction. "They deliberately overestimate that, which is a pure Machiavellian point of genius. If the sign says the wait is an hour, often it will be more like 45 minutes, which will make people feel like they're 15 minutes ahead of schedule," said Larson.

Walt Disney Imagineering -- the company's team of designers and engineers -- constructs the waiting line with the same care used for the attraction itself, adding games, interactive features and performances, and giving guests plenty to do. That keeps them from measuring the passage of time, which is typically the primary behavior in a queue. "If we increase our mental workload, if we occupy our mind, then we're not keeping track of time and, therefore, the wait seems shorter than it really is," Richard Ledbetter, a lecturer at Indiana University Bloomington, said in a phone interview.

A line outside an attraction at Disneyland Paris. Credit: BERTRAND GUAY/AFP/AFP/Getty Images

In a study titled "Practices for designing amusement park queues," Ledbetter sets out guidelines such as maintaining guests' level of interest in the attraction while in the line, facilitating personal interaction (which is why the line is never a single file unless unavoidable) and fostering engagement, which is the ultimate distraction. "That's why Disney, Universal Studios and other major parks are creating very engaging and themed wait time experiences. They almost become part of the attraction itself, so guests don't feel as though they're waiting in line for the attraction, but they're actually involved in it," he said.

According to Larson, Disney lines are so entertaining that on rainy days, when attendance is low, rides in the parks may fill up too slowly because families linger in the queue for too long. "If you have kids, they might think the ride has already started in the queue, because the amusements are so good," he said.

One delicate issue theme parks have to deal with are express lane tickets, which cost more but allow people to skip the queue. That goes against our desire for fairness in a line, so parks attempt to disguise express lanes as much as possible, making them merge into the main line at a later stage. Disney, for example, bypasses the issue by giving everyone the chance to book a free FastPass ticket, but only for one attraction at a time, which maintains a sense of fairness even if the express lane is clearly visible.

A boarding problem

Few places showcase the need for a good waiting line design better than airports. Check-in and baggage drop desks have almost all converted to serpentine lines, and security checks are slowly following suit. But there's a problem that airlines are still struggling to solve: boarding. It's often the cause of delays and -- no matter what system is in place -- many passengers prefer to stand up and queue rather than sit and wait for their boarding group to be called.

American Airlines, Delta, United and British Airways are among the major airlines that have changed their boarding procedures within the last year or so, with varying results. They all claim to have streamlined their processes, although these often involve five or more groups and color-coding.

Boarding systems are complicated because they have multiple goals: privileging families with young children, passengers with special requirements and those who purchased priority tickets, while also getting everyone on the plane on time. Tests suggest that the fastest strategy is to board alternate rows, window seats first, starting from the back of the plane -- a plan devised by Jason Steffen, an astrophysicist. It works because it avoids congestion in the aisle, which slows things down.

But a good, and less complicated second best is the "Wilma method," or letting people board according to their seat type: window first, then middle, then aisle. Letting all passengers in at once and allowing them pick their seats -- something European budget carrier Ryanair did until 2014 -- is also faster than what most airlines currently do, which is boarding by row, starting from the back of the plane.

Queuing around the world

When we face uncertainty as to how to behave in a line, we are forced into a mental stress that Larson calls "queue calculus." Some cultures have a natural aversion to this type of guesswork, such as Japan, where queues are meticulously signposted and most stations have colored patterns on platforms that indicate how to line up for upcoming trains.

In Latin countries, it's customary upon entering a waiting group to just ask who had been the last to arrive to know when your turn was up. Britain has such a stereotypical affinity for queuing that when a Brit stands still, the saying goes, they're forming a queue of one. In parts of Asia, people often tend to huddle more or less chaotically around a service point.

"In northern Europe, first come first serve is usually the accepted rule, while in southern, Mediterranean Europe cutting in line is a sport," said Larson.

However, sometimes these natural attitudes can be changed. McDonald's is credited with introducing orderly lines in Hong Kong in the 1970s through the aid of "queue monitors," employees who were tasked with channeling customers into a line.

People queue up on the opening day of the first McDonald's fast food chain restaurant in Hanoi, Vietnam. Credit: HOANG DINH NAM/AFP/AFP/Getty Images

The ultimate affront to line etiquette is, of course, cutting in. But if you have to do it, there is a disarmingly basic method that will give you a better chance of success. Harvard psychologist Ellen Langer has found in a classic study among people queuing for a copy machine that simply stating a reason to cut in ("Because I'm in a hurry") worked 94% of the time. That held true even if the reason given was ridiculous -- "Because I have to make copies" worked, astonishingly, 93% of the time. The magic word is "because." Good luck.